The invention relates to a digital solid-state trip unit for an electrical circuit breaker. The advantages of microprocessor-based digital solid-state trip units are well known, in particular the large number of possible functions and settings. The time required for digital processing is longer than that taken by analog processing and in the event of a high short-circuit, this delay might have harmful consequences for the circuit breaker. On start-up, notably when the circuit breaker closes, the device becomes operational after a certain far from negligible lapse of time, and in the case of closing on a fault, the installation and the circuit breaker are poorly protected.
The object of the present invention is to produce a digital trip unit having the advantages of analog systems.